Add a .travis.yml file.
Fix the Gemfile's RUBY_VERSION check.
Check the RUBY_ENGINE when determining dependencies.
Print out caller, which shows the weird to_proc call on 1.8.7.
A hacky fix for the 1.8.7 "method" method and to_proc bug.

See more here:
http://stackoverflow.com/questions/4721708/is-this-a-bug-in-methodto-proc-ruby-1-8-7